Reimagining one of American pop culture's most twisted mother-son bonds, Freddie Highmore and Vera Farmiga are perfect foils.

“Bates Motel” wields the word “normal” like a knife in the shower: Throw up your hands and scream bloody murder, but in the end there’s no deflecting it. In A&E’s strange, oft-sublime spin on “Psycho,” the term is an incantation, the protective spell that becomes a curse, and neither Norma Bates (Vera Farmiga) nor her son, Norman (Freddie Highmore), can maintain control of its unstable force. As a session with his therapist in the midst of the recent fourth season suggests, “normal” is the tune Norman whistles through the graveyard, unable to see that his insistence on the label is proof of the reverse. “Is that important to you, having your relationship described as ‘normal’?” Dr. Edwards (Damon Gupton) asks. “I just don’t think that we are abnormal,” the well-mannered murderer replies. “Yes, we’re close, but we had to be.”

Set in the years before Marion Crane turns up at Norman’s door, “Bates Motel” hinges on this unsettling arrangement, the point at which kinship crosses into convergence, and as such the series depends on the particular magic of its main performers. Highmore, rail-thin and retiring, is the perfect foil for Farmiga, bleached blond, blue-eyed, ferocious—their shared screen time generates the same sparks one might describe, in another context, as “chemistry,” the place where the shield meets the spear. Norma and Norman spoon, then spar; rage, then embrace; in one deliriously sick sequence, she tries to wrest a gun from his grasp by kissing him on the cheek, seductively edging nearer and nearer his lips, only to hear him suggest a suicide pact.

This is insane, but so is he: “Bates Motel” tasks itself with reimagining one of the most infamous villains in the American cinema, and the series’ foremost strength is its willingness to root around in the muck of Hitchcock’s psychological horror. Where the film’s suspense derives from the mystery of Mama Bates, from hiding the sordid truth in the camera’s high angles, A&E’s prequel revels, quite cannily, in showing its cards, patiently meting out the details of a doomed relationship. Cut with comic images—Norma wiping mud on her face—and knowing winks—Norman reading aloud of Pip’s love for Estella in “Great Expectations”—”Bates Motel” is the TV series as Freudian slip, the cold shiver of the subconscious always bubbling to the surface.

In the fourth season, the series’ finest to date, Norman becomes his mother, and it’s here that two complementary performances combine to form a single, surreal whole, the line between the characters blurring by degrees until it disappears entirely. Farmiga, as the object of Norman’s hallucinations and dissociative blackouts, seems to relish this more fantastical vein. Against the hunched, vulnerable figure desperate to protect her son, the wounded animal baring her teeth, the Norma of Norman’s deranged mind is voluptuous, slinking through strip clubs in a black feathered shawl—the femme fatale of a fragile psyche, peering over the precipice of high camp. It’s a bold, beguiling turn, and Farmiga’s gameness sells it: When Norman’s accomplice, a fellow escapee from a tony psychiatric hospital known as the Pineview Institute, interrupts her lap dance, she flashes an exasperated look, as if to say, “Damn, I was just starting to have fun!”

It’s Highmore, however, gaining new purchase on an iconic role, who carries “Bates Motel” up to the events of “Psycho,” which will be the subject of the series’ fifth and final season. As Norman twirls in a dresser mirror in his mother’s floral bathrobe, or vamps for Dr. Edwards during his descent into madness, the actor absorbs, by degrees, Farmiga’s mannerisms—the flirtatious laugh, the cunning smile, the awareness, born of Norma’s own trauma, that sex can function as both lure and cudgel, its power cutting both ways.

It is, for a 24-year-old performer in an industry that still prefers its leading men to play straight, a risky, surprising gambit, diving into the character’s queer currents with vigor. Channeling both Anthony Perkins’ reedy, fey serenity and Farmiga’s wily wrath, Highmore loses himself in Norman much as Norman loses himself in his mother, a subtly astonishing achievement. If he doesn’t receive an Emmy nomination this year, it’s the voters that need their heads checked.

The problem—even for Farmiga, nominated in 2013 for the series’ first season—is that discovering the daring performances of “Bates Motel” requires wading into territory the TV Academy rarely deigns to touch. There’s the outré subject matter (incest! necrophilia! voyeurism!), the genre itself (which only Ryan Murphy, in the Limited Series race, seems to have cracked), and the shadow of Hitchcock’s classic (an impossibly high standard). More to the point, “Bates Motel” is still hobbled, in stretches, by dispiriting narrative detours: Norma’s marriage to Sheriff Alex Romero (Nestor Carbonell), a long-awaited lung transplant, a bunch of nonsense about money laundering and secret sex parties and the local pot trade. Highmore and Farmiga are the shoots poking up through the rubble, still delicate enough to be crushed.

Hitchcock’s insight, in “Psycho,” was to recognize that Marion Crane is a wedge in the door to Norman’s world, not its center of gravity, and in stripping the story bare the director squared space for the abnormal to become normal, at least as long as the film’s spell was cast. By the time “Bates Motel” dissolves from room to room in that foreboding Queen Anne mansion, an eerie rendition of “Mr. Sandman” ringing through its halls, the series gestures at this simpler structure, reducing its universe to the space between Norman’s ears. On the strength of Highmore and Farmiga’s dual, and dueling, turns, “Bates Motel” soars, without recourse to any machinations but their own. “My whole life, you have kept me so close to you that I couldn’t breathe without you,” Norman accuses at one point, and in the new normal left in the wake of the fourth season, he and his mother are closer than ever.